1. Field of the Invention
The present invention relates to a system for preventing the flooding of a dwelling, and, more particularly, to an apparatus for generating a mechanical output responsive to the presence of leaking water to prevent water damage.
2. Description of the Background Art
The flooding of dwellings caused by a failure in the water supply system is a well known problem. Specifically, broken water lines, or the failure of appliances such as hot water tanks and automatic washers, have been responsible for extensive property damage caused by the internal flooding of a dwelling. Such a problem can be further exacerbated in multi-story structures where there are numerous hot water tanks, each of which expose multiple units to potential water damage.
Accordingly, a number of devices are known in the prior art for shutting off water flow in a dwelling in the event of an internal rupture in the plumbing system. U.S. Pat. No. 5,008,650, issued to Hoiberg, discloses a battery-powered, liquid-detection alarm and shut-off system including an elongated sensor, an electronic controller, and a spring biased shut-off valve assembly. However, the system disclosed by Hoiberg requires the installation of a specialized shut-off valve assembly in the plumbing system thereby complicating installation.
Another prior art device is disclosed in U.S. Pat. No. 4,297,686, issued to Tom, which discloses a resistive liquid detection and shut-off system used to protect a floor area from water damage. Tom also teaches a system requiring extensive installation and wiring from the liquid sensor to a specialized water shut-off solenoid valve which must be installed in the plumbing system. In addition to the disadvantages of having to install a specialized solenoid valve, the fact that solenoid valves require continuous electrical current to operate mandates additional wiring. Furthermore, Tom teaches use of a tape water sensor which would have to be run throughout the dwelling and is subject to failure in the event of a break in the tape.
Yet another prior art device is disclosed in U.S. Pat. No. 5,240,022, issued to Franklin. The Franklin device also requires the installation of a specialized spring loaded ball valve in the water supply line; such installation requirements result in a system that can not be easily moved from one appliance or structure to another. Finally, the Franklin system does not preserve full manual actuation of the valve.
U.S. Pat. No. 5,409,037, issued to Wheeler et al., discloses an automatic device for the detection and shutoff of excess water in pipes using a microphone. The Wheeler device has a complex control panel and a motorized actuator mounted and anchored to a manual valve stem using sheet metal screws and a metal bracket. The Wheeler device, however, detects water flow within a pipe and does not detect water leaking from a pipe. Furthermore, the Wheeler device is not sufficiently sensitive to detect small (pin hole) leaks which result in insignificant overall flow within a pipe, and is overly sensitive to large leaks, and further provides no protection when turned or scheduled off. Furthermore, in a residential application it may be desirable to turn the Wheeler device off for substantial portions of time to allow for water usage around the clock.
U.S. Pat. No. 4,488,567, issued to Grant, discloses an automatic valve closer mounted and anchored to a valve by a complex metal bracket. The valve closer disclosed by Grant is triggered by an electrolytic switch which includes a container having salt and a pair of contacts therein such that leaked water entering the container causes the salt to dissolve forming an electrolytic solution that conducts electric current and closes the circuit. Grant, however, does not disclose the structure of such a salt filled container and it is believed that such a triggering mechanism suffers from disadvantages relating to sensitivity and reliability. In addition, the metal bracket mounting assembly disclosed by grant results in metal to metal contact with the pipe system thereby causing corrosion of the water pipe from an electrolytic reaction between the pipe and the metallic bracket components.
A number of other patented devices suffer from similar disadvantages, as well as a number of additional shortcomings. For example, many prior art devices contemplate an alarm as the main function thereby leaving the possibility of extensive damage if triggered when the dwelling were vacant or if the alarm were not heard. Further, many prior art devices are designed to protect one relatively small area, and others have proven too complex or difficult to install, and, have not gained wide acceptance. It is to these prior art disadvantages that the present invention is directed.